Peterson and Khan were due to meet in a major HBO “World Championship Boxing” main event on May 19 at Mandalay Bay in Las Vegas, six months after their epic first encounter, in which Peterson won a controversial split decision in his hometown of Washington, D.C., to take a pair of world title belts from England’s Khan.

Peterson (30-1-1, 15 KOs) initially denied he had taken synthetic testosterone when his “A” sample tested positive April 12. After the “B” sample also tested positive May 3, Peterson said he had taken testosterone pellets under a doctor’s supervision — at a clinic in Las Vegas — because he suffered from fatigue and had difficulty concentrating.

According to letters from doctors that Fried submitted to the NSAC, and obtained by ESPN.com., Peterson was diagnosed with abnormally low testosterone levels.

Taking the substance is a violation in Nevada, according to Kizer. Taking a substance for medical reasons and not disclosing it is also a violation under Nevada rules.

“There’s no question about it that Peterson was injected or inserted with testosterone pellets,” Schaefer said. “They don’t deny it, but it raised a lot of questions. He trains in Washington, D.C., so why would he go to Las Vegas to a little clinic which the Nevada commission never even heard of and get tested because you feel you’re tired? Aren’t there better places in Washington, D.C., which has a lot of great hospitals, to do that?”